Drafting instrument



K. POULSEN DRAFTING INSTRUMENT Oct. 2,1934.

Filed Sept. 22, 1930 2 Sheets-Sheet. 1

Oct. 2, 1934. PQULSEN 1,975,648

DRAFTING INSTRUMENT Filed Sept. 22, 1930 2 Sheets-Sheet. 2

44 7 IIIIIIIIIIIIIIIA Patented 0st. 2, 1934 STATES mrs DRAFTINGINSTRUMENT Knud Poulsen, Racine, Wis, assignor to Sterling Tool Company,Racine, Wis.

Application September 1 Claim.

This invention relates to improvements in drafting instruments.

One of the objects of the present invention is the provision of animproved drafting instrument wherein the parts are interchangeable andadjustable so as to simplify the construction of a drafting instrumentof this character and provide an instrument which can be used forvarious purposes and including difierent types of scales which can beinterchanged, as well as improved adjusting mechanism for the rulingmembers.

Another object of the present invention is the provision of a draftinginstrument which is provided with means for adjustably mounting theinstrument upon a drafting board so that the the device can be adjustedto various positions withrespect to the table, and the ruling membersare provided with measurements laid out in different scales, and arereversible so that the position of the same can be quickly and easilychanged to use the scale on either edge of the rule.

A further object of the present invention is the provision of a draftinginstrument which aims to reduce the cost of construction of such aninstrument, as well as to simplify the construction of the same, and atthe same time incorporate in an instrument of this character varioustypes of scales so that the instriunent can be used for variouspurposes, not only for squaring different angles, but for protractingpurposes, whereby the instrument can be used in a great many Ways.

With the above and other objects in view, the invention consists in thenovel features of construction, the combination and arrangement of partshereinafter more fully set forth, pointed out in the claim and shown inthe accompanying drawings wherein:

Figure 1 is a plan view of an improved drafting instrument constructedin accordance with this invention;

Figure 2 is a top plan View of the body portion with parts removed;

Figure 3 is a bottom plan view of the body portion;

Figure 4 is a section on the line 4-4 of Figure 1;

Figure 5 is a detailed section on the line 5-5 of Figure 1;

Figure 6 is a detailed section on the line 6-6 of Figure 4;

Figure '7 is a detailed section on the line '7--7 of Figure 3; and,

22, 1930, Serial No. 483,633

Figure 8 is a plan view of the adjustable segment.

Referring more particularly to the drawings, it will be noted that Iprovide an arcuate body plate 1 which is formed at its arcuate edge withspaced divergent arms 2, the outer ends of which carry guide wheels 3adapted to cooperate with the guide rail 4 positioned on a draftingboard. The guide wheels 3 cooperate with a third wheel 5 positionedcentrally of the two arms 2, and carried by a movable. arm 6.

The arm 6 is pivotally mounted upon the body at the inner end of one ofthe arms 2 by means of a pivot pin 7 and the outer end of arm 6 carriesa lateral projecting lug 8 struck out from the body portion of the armand against which the spring member 9 abuts. This spring memher 9 isattached to the body of the plate 1, as shown at 10, and stop pin 11limits the movement of spring member 9 in one direction when pressure isapplied to wheel 5. The body plate 1 has attached thereto at the sideopposite the arms 2, the base portion 12 of the divergent guide arms 13.

The ruling members 14. have attached to both ends thereof the headedstuds 15 which are received in openings 16 in the arms 13 and threadedportions 14' are carried by ruling members in spaced relation with theheaded studs 15 to receive the retaining screws 15 which are passedthrough transverse slots 16 in the arms 13, as shown at Figure 4 forretaining the ruling members 14 in various adjusted positions relativeto the arms 13.

The retaining screws 15 are provided with knurled head pieces 00 wherebythey may be readily engaged or disengaged from the sleeves 14' whenattaching the ruling members to the arms 13. It will be noted that theruling members 14 are provided along one edge with one type of scale,while the other edge has thereon another type of scale, and by means ofthe construction illustrated, the ruling members can be quickly reversedas to their position with respect to the body 1 so that either type ofscale can be used whenever desired.

It will also be noted that by providing arms 13 with the slots 16, itpermits lateral adjustment of the ruling members 14 with respect to thebody 1 so as to compensate of any displacement of the guide rollers 3and 5, whereby a true angle can be maintained at all times. In adjustingthe ruling members 14 with respect to the arms 13, it will be noted thatthe headed studs 15 act as the pivot point for the ruling members.

Arranged upon one face of the body 1 and conforming to the arcuate shapeof the outer edge is an arcuate plate 17 provided with a series ofgraduations adapted to be used in connection with the plate 20. Thisplate 17 is provided with spaced indentations 18 engaged by a ball 19movable with plate 20, with the ball 19 urged into any one of theindentations 18 by means of a spring 21 carried by plate 20.

The base portion 12 of the divergent arms 13 carries a central shaft 21which extends upwardly through plate 1, and through the opening 22 ofplate 20, a hand wheel 23 being attached to the upper end of shaft 21and provided with a cen-- tral part 24 engaging a clamp nut 25 whichfrictionally engages the upper face of plate 20 to move the same overthe arcuate plate 17.

The plate 20 is provided with an arcuate slot 26 which receives theupstanding threaded pin 11 carried by the body plate 1, and a wing nut27 is attached to the upper threaded end of pin 11 and engages aclamping washer 28 for retaining plate 20 against movement. However, assoon as nut 27 is rotated a slight distance to release plate 20, thehand knob 23 can be rotated for moving the plate 20 over the main bodyplate 1 and the scales on plate 17 may be easily read. Thus, by usingthe lug 8' as an indicating pointer, the ruling members 14 can be set atthe desired angle relative to the scale 17 and thus permit the device tobe used for protracting purposes.

It will be apparent from the foregoing that I have provided a verysimple and inexpensive type of drafting instrument which can be slidablymounted upon a guide rail of a drafting board and wherein the rulingmembers 14 may be quickly changed as to their position by turning themend for end and attaching them to the guide arms 13, so that the twodiiferent scales on the edges of the ruling members can be used atdiiferent times.

A drafting instrument constructed in accordance with the abovedescription will be very inexpensive to manufacture and at the same timewill provide an instrumentwhich can be used for a great many purposesand can be adjusted for various angles to permit the same to be used forprotracting purposes.

While I have shown and described the preferred embodiment of myinvention, it will be apparent that slight changes may be made in theconstruction when putting the invention into practice without departingfrom the spirit of the same or the scope of the appended claim.

I claim:

In a drafting instrument, a semi-circular body plate having divergingarms thereon and an opening therein, means on the arms and plate forengaging a stationary guide, a pair of right angularly disposedsupporting arms rigidly connected together and having an opening thereinat the point of. connection thereof, said arms being disposed at theirpoint of connection on the body plate, straight edge members secured tothe supporting arms, a scale plate secured to the body plate, a sectorplate with an indicating edge movable over the scale plate, said sectorplate having an opening therein registering with the opening in the bodyplate and the opening in the supporting arms, and releasable meansextending through said openings for connecting the supporting arms andthe sector plate together for movement relative to the scale plate.

KNUD POULSEN'.

